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Wall Charger Tripping AFCI's on Other Circuits

Discussion in 'Model 3: Battery & Charging' started by Kruger, May 17, 2019.

  1. qdeathstar

    qdeathstar Active Member

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    #21 qdeathstar, Dec 5, 2019
    Last edited: Dec 5, 2019
    This is an interesting issue.. i wonder if the chargers are lacking noise suppression and the afci breakers are seeing that noise as as an arc...

    Here is an approximation of what an afci sees under fault conditions.

    upload_2019-12-5_19-27-24.jpeg

    So, i’m not sure what is in the wall chargers but i there is some sort beefy capacitor in there it could generate some kinda noise while the capacitor charges....

    Another view....

    upload_2019-12-5_19-30-0.jpeg

    upload_2019-12-5_19-30-0.jpeg

    Arc Detection with the AFCI - IAEI News magazine
     
  2. Scrannel

    Scrannel Member

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  3. SilverSp33d3r

    SilverSp33d3r Member

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    I’ve had the same issue. Mine was not actually the car charging itself it was caused when my car was charging and the refrigerator kicked on or the Hairdryer. Went and checked those neutrals at both the panel and receptacles, ended up being the receptacle creating an arc condition exasperated by a slightly lower voltage replaced and problem solved.

    Does it trip everything when just powering on or when plugging the car in? In other words is it immediately or delayed?
     
  4. toolman335

    toolman335 Member

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    This ^^^^^^^^^^

    It is very unlikely that this is a Tesla issue. I agree with the comment that electricians miss things. I am a bit frightened that the OP appeared to be working on some of this stuff himself? Yikes. No matter what you tweak in this world, if it's done incorrectly it can lead to seemingly unrelated issues.
     
  5. eprosenx

    eprosenx Active Member

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    I have been watching this thread with interest but have not chimed in as I did not have any clear advice.

    So tripping AFCI on an unrelated circuit is really weird. I am thinking there are a few ways that the Tesla could influence this:

    1. As the Tesla ramps up charging it may be pulling the voltage down on your service over all. There may be some condition on that AFCI branch circuit that was very close to tripping the circuit but it did not quite do it. Once the voltage is dragged down enough it may put it over that threshold. (AFCI trip mechanisms are complicated and driven by a microprocessor)
    2. The Tesla may be creating some kind of noise or harmonic on the electrical service that again is pushing the AFCI over some limit. This would be really hard to troubleshoot without advanced tools and skills. We have seen Tesla’s trip some GFCI breakers, perhaps for similar reasons.
    3. AFCI’s also I believe have some basic ground fault circuitry in them. This is more of a long shot, but if there was some really weird leakage of current from the Tesla circuit into the AFCI circuit (to like nicked wires that are touching in the same conduit) it could cause an issue like this. But that is such a long shot I don’t even think I should have mentioned it.

    My first course of action here would be to look at the voltage when you first plug the car in (immediately before charging starts) and then compare that to the voltage after the car fully ramps up and has been charging for a minute or so. If that drop is excessively high that could indicate other issues.

    Next, I would troubleshoot the circuit in question. There are two paths you could start with:

    1. Replace the breaker with a new one. The newer models may be a little less sensitive than the old ones (I would check if your current breaker is still sold or if it has been superseded by a new one). This by itself could solve it if your breaker is bad or just the old model is overly sensitive.

    2. The other thing to do is to try to track down a device on the circuit that may be causing it. Catalog every receptacle/light/device on the circuit and disconnect/turn things off and see if the issue occurs. It could be a bad device that has a legit frayed cord and is causing arcing, or it could just be a device that always causes nuisance trips (that is not otherwise malfunctioning). If is not obviously isolated to one device, then you may need to tear into every single receptacle/switch box/junction box and make sure all the wires are right and not touching each other. I recently upgraded my in-laws to some a AFCI breakers and they were having nuisance trips when running relatively high current loads on the circuit (but not isolated to a single device). I found a receptacle where the bare ground wire was touching the neutral screw. So this had probably been that way for decades. Some current was returning to the transformer via the ground path rather than via the neutral. This was causing trips on the AFCI breaker since it also has some
    GFCI like functionality.

    I know this sucks, but these issues can be very difficult to troubleshoot. I do find is extremely odd that the Tesla causes nuisance trips on unrelated 120v circuits! Not good!

    Please do report back on any resolution or new learnings!
     
  6. spookygeek

    spookygeek New Member

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    Swapped out the breaker this afternoon for a brand new one. Old one is maybe 10 years old. So far so good. Full load charging for maybe 2-3 hours and no issue. I think this all goes back to a old and maybe out of spec afci.

    I’ll do some more charging over the next few days to confirm, but I’m hopeful I’ve got this thing sorted now.
     
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  7. spookygeek

    spookygeek New Member

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    I've done a lot of charging over the last few days and no issues to report at all. Pretty confident it was just an out of spec AFCI breaker giving me the trouble. Hopefully this can help others if they run across this odd issue in the future.
     
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  8. Cane811

    Cane811 New Member

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    I’m in a newer home and having AFCI issues on other circuits. Still no issue after switching out breakers?

    Thought about buying a Gen 1 mobile connector to see if that helps.

    I’m having random circuits tripping while my Tesla charges. Looking for any help.
    Electricians are bleeding me dry haha.
     
  9. sadak.shaik

    sadak.shaik New Member

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    I have a model Y and my home was built in 2020. I have the Tesla wall charger (2nd Gen). I have the same issue as mentioned above. I have a 50amp breaker on the wall charger and I have set the wall charger at 9 (40amps). After few mins of charging, a whole bunch of other AFCIs get tripped. The electrician who did the electrical work for my entire house looked at it and is asking to change all the breakers to GFCI since he tried replacing the new AFCIs and they had the same issue. Any resolution will be greatly appreciated.

    thanks
     

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